Python vs C for a mail server

[abhinav]

Hello guys,
I am a novice in python.I have to implement a full fledged mail server
..But i am not able to choose the language.Should i go for C(socket API)
or python for this project? What are the advantages of one over the
other in implementing this server.which language will be easier? What
are the performance issues?In what language are mail servers generally
written?

[Steven D'Aprano]

On Fri, 27 Jan 2006 22:43:48 -0800, abhinav wrote:

Hello guys,
I am a novice in python.I have to implement a full fledged mail server
Because that's just what the world needs, yet another mail server.

Why don't you use an existing mail server?
.But i am not able to choose the language.Should i go for C(socket API)
or python for this project?
If you aren't able to choose the language, what does it matter what we
say? Somebody else will choose.

What are the advantages of one over the
other in implementing this server.
C can be faster.
which language will be easier?
Python is easier to read, and write, and debug, and you will have fewer
hard-to-debug memory issues.
What are the performance issues?
You will spend hundreds of man-hours re-inventing the wheel.

In what language are mail servers generally written?

Google is your friend. The first four mail servers listed are, in order:

sendmail
postfix
Microsoft Exchange
qmail

Of the four, source code is available free of charge for three of them.
Can you guess which is the odd man out? :-)
--
Steven.

[Ravi Teja]

>> Why don't you use an existing mail server?

Probably because that was his homework assignment for a networking
class. Not uncommon to be told to implement a server from the scratch
from the RFC. Although that does not explain his concern about
performance.

Abhinav, if that is the case, using sockets is more or less the same
from any language. Python as usual will be cleaner than C. You might
want to look at Twisted Mail. Use SocketServer module in the standard
library to implement the RFC. Other than that it is silly to try to
write a Mail Server unless you have some extra ordinary need.

[al pacino]

>but i am not able to choose the language.Should i go for C(socket API)

Ravi is right
(>using sockets is more or less the same
from any language.)

...try JSP(java server pages), some guys in nit warangal implemented a
mail server
(foa LAN though)for their minor project.

my contention is that using sockets(in c++) will improve your
understanding of the protocol
suite and improve your programming as well.


Ravi Teja wrote:

Why don't you use an existing mail server?

Probably because that was his homework assignment for a networking
class. Not uncommon to be told to implement a server from the scratch
from the RFC. Although that does not explain his concern about
performance.

Abhinav, if that is the case, using sockets is more or less the same
from any language. Python as usual will be cleaner than C. You might
want to look at Twisted Mail. Use SocketServer module in the standard
library to implement the RFC. Other than that it is silly to try to
write a Mail Server unless you have some extra ordinary need.

[Jim Segrave]

In article <11************ *********@g43g2 000cwa.googlegr oups.com>,
Ravi Teja <we*********@gm ail.com> wrote:

Why don't you use an existing mail server?

Probably because that was his homework assignment for a networking
class. Not uncommon to be told to implement a server from the scratch
from the RFC. Although that does not explain his concern about
performance.

Abhinav, if that is the case, using sockets is more or less the same
from any language. Python as usual will be cleaner than C. You might
want to look at Twisted Mail. Use SocketServer module in the standard
library to implement the RFC. Other than that it is silly to try to
write a Mail Server unless you have some extra ordinary need.

Any lecturer assigning "write a mail server" as a class project is
doing his/her students a true dis-service. Mail server RFC compliance is a
nightmare to get right, performance issues and mail routeing are both
material for at least a full year's university study.

A student who tries to make an even vaguely RFC compliant mail server
probably won't finish their project, as student who completes such a
project might come away with the mistaken belief that they actually
have done it correctly.

The number of software products which use eail and do so incorrectly
is astounding and depressing. There's a reason that the source for
sendmail is about 120K lines, exim is nearly 270K lines. Doing it
right is _hard_.

--
Jim Segrave (je*@jes-2.demon.nl)

[al pacino]

jim you are probably right.

i have had exp. with this. i had to create a server(multipur pose such
as file sharing, games (pretty simple tho like tic tac toe..) we were
in 6th sem with learning OS and comp. n/w for the first time.

it seems like these jack ass jerks (proffs/instuctors) like to bully
students...
obviously we cud not complete the project as most of the time was spent
on
learning the stuff(like TCP, multithreading. .) .

i don't know how things work out in the west, but i feel the faculty
really care about their students in american colleges..in contrast to
here (in inida, though things are little different in the IITs)
Jim Segrave wrote:

In article <11************ *********@g43g2 000cwa.googlegr oups.com>,
Ravi Teja <we*********@gm ail.com> wrote:

Why don't you use an existing mail server?

Probably because that was his homework assignment for a networking
class. Not uncommon to be told to implement a server from the scratch
from the RFC. Although that does not explain his concern about
performance.

Abhinav, if that is the case, using sockets is more or less the same
from any language. Python as usual will be cleaner than C. You might
want to look at Twisted Mail. Use SocketServer module in the standard
library to implement the RFC. Other than that it is silly to try to
write a Mail Server unless you have some extra ordinary need.

Any lecturer assigning "write a mail server" as a class project is
doing his/her students a true dis-service. Mail server RFC compliance is a
nightmare to get right, performance issues and mail routeing are both
material for at least a full year's university study.

A student who tries to make an even vaguely RFC compliant mail server
probably won't finish their project, as student who completes such a
project might come away with the mistaken belief that they actually
have done it correctly.

The number of software products which use eail and do so incorrectly
is astounding and depressing. There's a reason that the source for
sendmail is about 120K lines, exim is nearly 270K lines. Doing it
right is _hard_.

--
Jim Segrave (je*@jes-2.demon.nl)

[abhinav]

ya its supposed to be some stupid 6 month project which my friend has
to do.I am just helping him out.he may not be implementing a full
fledged rfc compliance mail server but may support some of the major
functionalities .so basically its an extra ordinary need.I just wanted
to know which language would be better for implementation and has
faster development cycle.I have heard a lot about python and its ease
of use.My point is it should be worth a 6 month project and speedy
development since he is already proficient in C/C++ socket programming
and taking the pain of learning python should be worth the effort.

[Nicolas Lehuen]

If your friend is proficient in C/C++ then learning Python should not
be a pain. Quite the contrary, it should be an enlightnement. Being
good in C/C++ AND Python is a killer combination, as you can promptly
and efficiently code big chunks of your application in Python and
interface with C/C++ code where (and if) high performance is required.

Now, you should definitely check the requirements for the homework.

If the assignment is about being able to decipher an RFC and implement
it correctly with a nice software design, then I would definitely opt
for Python. Having to squish memory management, string manipulation and
character encoding bugs in C/C++ is not fun and not related to
high-level design nor RFC support.

If it's just a way to throw a programming challenge at your friend's
face, then you should check whether it's okay to use Python rather than
C/C++, otherwise he could be charged of cheating by using a more
productive language :).

Regards,
Nicolas

[Jens Theisen]

Nicolas wrote:

If it's just a way to throw a programming challenge at your friend's
face, then you should check whether it's okay to use Python rather than
C/C++, otherwise he could be charged of cheating by using a more
productive language :).

Though this comment of mine is likely to start a religious war, it might
also bring up some useful points.

I'm a bit relucted to swallow the common view of Python being a so-
productive language, especially compared to C++. I value C++
productiveness actually much higher than it's performance.

To stick to the mailserver example, I'm pretty sure I'd do it in C++. I
got very exited about Python when I first saw it, but I've encountered
several problems that hindered productivity dramatically.

One thing is the lack of static types. The problem is not only that the
compiler can't tell you very basic things you're doing wrong but also that
code isn't intrinsically documented:

def send_mail(mail) :
...

What can I do with mail? In C++, you're looking up what type it is
(presumably by pressing M-x in Emacs on the word before it) and have a
look on it's type definition. In Python, it can be quite difficult to tell
what you can do with it because the information of what will be passed in
can be several layers up.

Also there is not even symbol-safety: self.not_define d will never rise a
compile-time error.

And to address the memory management critisism about C++: Unless you have
cyclic structures (you probably won't have in a mail server), just use
smart pointers and you don't have to be concerned more about it than you'd
have to be in Python.

I aggree on C++ libraries being weak on unicode strings though, or even
generally weak in the libraries (you have the C libraries, but they're not
very type safe or elegant to use).

I'm aware that C++ is a horrible monstrosity, an argument whiches weight
depends on the OP's friends C++ experience.

Please don't be offended, but if anyone could make a point of how Python's
disadvantages in these regards could be alleviated, I'd be very
interested.

Jens

[Sybren Stuvel]

Jim Segrave enlightened us with:

Any lecturer assigning "write a mail server" as a class project is
doing his/her students a true dis-service.

At one time, I got an assignment "Write a robust, user friendly SMTP
client". That was just after we learned how to user 'for' loops and
'if' statements. Talk about dis-services ;-)

Sybren
--
The problem with the world is stupidity. Not saying there should be a
capital punishment for stupidity, but why don't we just take the
safety labels off of everything and let the problem solve itself?
Frank Zappa